New 90 gallon Malawi diy build

[Hydroponicfish]

I am currently setting up a 90-gallon tank I got on Craigslist. It will have a HOB overflow, 30 gal bioball wet/dry, a 50 gallon refugium (my old display tank), with aquatic and aquaponic plants. I will also be growing anubias and sacred lotus in the main tank as it is hardy, deep rooted, fast growing, large, hard water plant and many people have successfully kept the smaller tiger lotus with mbuna. I have two 300 gph submersible pumps I got from the previous owner of the tank and my old 350 gph magnum 350 canister that I don’t like and don’t want to use and two bubble pumps rated for 10 gallon tanks and one for a thirty rigged to a collection of airstones. I intend to allow the tank to cycle with daphnia in the sump before I put any fish in. I have never kept any cichlids other than angels before and want start with African cichlids.
Is my filtration inadequate? I intend to upgrade anyway, but although this may be low gph, there is a massive amount of bio and plant filtration.
Do I need/want activated carbon in my filter(s)?
I have hard water from the tap and intend to do a lot of buffering (limestone in the main tank and coral sand left over for my hermit crabs in a reactor) Can I make the refugium a dirted tank?
Has anyone kept a sacred lotus with Malawi cichlids before and what was the result?
I am somewhat strapped for cash. Can I just get three Cyrtocara moori aka Blue Dolphins and five Labidochromis caeruleus aka Yellow Labs and let them breed, as I only want these two species anyway, or will the understocking (8 fish/90 gallon tank) cause them to rip one another to shreds?
Is there anything that will leave the algae on the rocks, but remove it from the glass?
I want to run each of me 300 gph pumps through a separate line one with ugj and co2 and the other with a spraybar. Is there any reason not to do this and were should I put my spray bar so its not blowing straight intot the over flow as the tank will be mounted in a wall and visible from both a sides so the overflow box is at one end of the tank, hidden in the wall?

[Autumnsky]

That is a lot to consider. My thought is about the plants, Anubias comes in different sizes and leaf shapes. That I have seen will often work in Cichlid set ups. My Cichlid knowledge is pretty limited so for all the rest I will hope some one more knowledgeable will help confirm or steer you in the right direction.

[Tpalmer]

I have a 90 gal with 24 mixed male Malawi's and two fluval 405 for filtration. I never use carbon unless I want to take out medication which is really the only use for carbon. U want to filter your tank anywhere from 5 times and hour to 10 times an hour depending on stocking level. If ur under stocked the 600 gph of the pumps may be enough. Is the hob overflow rated to a gph? That would be your limiting factor. I would to over filter as much as you can with Africans. They love the current and are very dirty fish in general. If you can't afford to over filter maybe try to add cheap power heads to get rid of dead spots and increase the water flow around the tank. As far as algae on the glass goes ur gonna have to scrape it off. Try a mag-float glass cleaner. I have one is each of my tanks and they work great. I don't know anything about refugiums, plants or breeding sorry.